We just celebrated DH's 30th at MK in January. We got his button when we got to the Park and he got a phone call from Goofy wishing him a happy birthday. We also got a "fast pass" to use on ANY one ride at ANY time without restrictions (ie we could still get other fast passes and could use it on rides that don't have the fast pass option). It was a nice way to start the day. Everyone around the park wished him a happy birthday, this included other vistors, not just CMs. However, just before the parade started, one of the CMs noticed his button and made him stand up in the middle of main street and asked everyone to sing happy birthday to him. He was so embarrassed (I loved it).
We had reservations at CP for dinner that night. When we arrived to the table, they hostess decorated the table with streamers and confetti. Just before we left, he got a birthday card signed by all the "Pooh" characters. I also pre-ordered a personalized cake to be brought to the table with candles. The person who I booked the reservations with told me that they normally bring out cupcakes with candles, but being his 30th, I wanted something he would remember.
I also told the resort it was his birthday, so when we got back to our room that night, there was a signed birthday card from Mickey as well as an autographed picture and some balloons.
DH said it was the best way to celebrate his birthday. You have to love all the touches that Disney does to make your day special.